The use of hydrogen as a carrier of energy, particularly in the context as a fuel, has the following significant technical advantages over other energy sources.
1. Supply side considerations--hydrogen is inexhaustible, storable, transportable, and has a high energy density compared with other chemical fuels. PA1 2. Demand side considerations--hydrogen is non-polluting, more versatile than electricity, more efficient than petrol, and convertible directly to heat and electricity for both mobile and stationary applications. PA1 (a) the electrical energy conversion means is adapted for receiving and for converting the shorter wavelength component into electrical energy; and PA1 (b) the thermal energy conversion means is adapted for receiving and converting the longer wavelength component into thermal energy.
By way of particular comparison, the large scale use of solar energy as an energy source has been limited for technical reasons and cost by a lack of a suitable short and long term storage medium for solar energy.
However, notwithstanding the above technical advantages of hydrogen as an energy source, the cost of production of hydrogen has been too high hitherto for widespread use as a fuel.
In the case of the production of hydrogen by electrolysis of water, a major factor in the high cost of production has been the cost of electricity to operate electrolysis cells.
In the specific case of solar radiation-generated electricity, the high cost of electricity is due in large part to the relatively low efficiency of photo voltaic (or thermal) conversion of solar energy into electricity which means that a relatively large number of photo voltaic cells (or, in the case of thermal conversion, a large collection area) is required to generate a unit output of electricity.